The solvent systems for solubilizing pharmaceuticals such as ibuprofen for encapsulation into soft gelatin capsules are well known in the art. A typical system is described in U.S. Pat. No. 4,690,823 to Manfred Lohner et al which describes soft gelatin capsules containing a solution of from 15 to 30 parts by weight of ibuprofen in a polyoxyethylene-polyoxypropylene polymer or in a mixture of a polyalkylene glycol and a surfactant. Suitable surfactants exemplified are polyoxyethylene-(40)-glycerol trihydroxystearate polyoxyethylene-(20)-stearyl alcohol, and polyoxyethylene-(20)-sorbitan monostearate. Because of its detailed description of solvent systems for solubilizing ibuprofen, U.S. Pat. No. 4,690,823 is incorporated herein by reference in its entirety.
Another description of solvent systems for solubilizing pharmaceuticals such as ibuprofen for encapsulation is given in U.S. Pat. No. 5,071,643 to Man S. Yu et al which describes solvent systems for ibuprofen comprising polyethylene glycol containing 0.2 to 1.0 mole equivalents of an ionizing agent of the hydroxide species per mole equivalent of ibuprofen. Suitable ionizing agents disclosed are potassium hydroxide, sodium hydroxide and ammonium hydroxide. The disclosure of U.S. Pat. No. 5,071,643 is also incorporated herein in its entirety.
U.S. Pat. No. 4,690,823 exemplifies solutions for incorporating into soft gelatin capsules of a suitable size wherein 0.880 grams of solution contains 200 milligrams or about 23% ibuprofen. U.S. Pat. No. 5,071,643 discloses solutions containing as high as 67% ibuprofen. The ionizing agents used as solubilizing enhancers for ibuprofen contain a highly reactive hydroxide ion which may react with other ingredients in the solution or with the capsule shell.